There is an ongoing effort in making electronic devices more intelligent, more powerful, less energy consuming, and more compact. This effort has lead to reduce the structure size of integrated circuits to a scale smaller then 100 nm. In view of this evolution, it has become a challenge to connect integrated circuits to an outside world that usually deals with a scale of the size of the human body. Packaging is seeking to bridge this scale difference. For example, by attaching and wire bonding an integrated circuit to a leadframe, the small wire bond pads of an integrated circuit are electrically connected to the leads of the leadframe that in turn are solderable to the larger pads of a printed circuit board of an electronic appliance. Further, by encapsulating the integrated circuit with a mould material, the fragile integrated circuit and bond wires are protected from the environment.
In order to increase functionality of integrated circuits, bonding wires have often been replaced by bumps placed on the chip surface. Using bumps helps increasing the number of input/output channels for a given integrated circuit area. Further, to increase functionality density, stacking of integrated circuits one atop the other, before molding the stack, has been introduced.
Bump bonding, as well as stacking chips or substrates, pose several challenges. For this and other reasons, there is a need for the invention disclosed below.